John Tzelepes Komnenos

As a young man he followed his father during his exile and wanderings across Asia Minor and the Levant, when for a short time he was married to a daughter of Leo I, ruler of Armenian Cilicia.

After the reconciliation between his father and his uncle, Emperor John II Komnenos, in 1138, he returned to the Byzantine court, but defected in the next year to the Danishmendid Turks during a siege of Neocaesarea.

The reasons for this are left unexplained by the sources; Niketas Choniates and John Kinnamos simply report that Isaac had set his sights on the throne.

The conspiracy was uncovered, but Isaac and his two sons managed to flee Constantinople and find refuge at the court of the Danishmendid emir Gümüshtigin Ghazi (r. 1104–1134) at Melitene.

[5] John accompanied his father during his subsequent six-year exile, during which time they traversed most of Asia Minor and the Levant, as Isaac tried to rally the region's rulers to his cause against his brother.

The emperor's military successes, particularly following his Syrian campaign in 1137–1138 that led to the submission of the Principality of Antioch to the empire, enhanced his standing with the Byzantine aristocracy, officialdom, and the common people.

John readily divulged what information he was privy to about the weaknesses of the Byzantine army, chiefly a lack of supplies and horses; this act probably saved Neocaesarea from falling, and the emperor was left with no choice but to withdraw.

[15][19] As Konstantinos Varzos points out, this descent is unlikely, purely due to the chronological distance of the persons involved,[20] and has generally been dismissed as fictitious by modern scholars.